[mpeg-OTspec] Re: [OpenType] RE: Proposal: deprecate ReqFeatureIndex

[Sairus Patel]

Peter,



On 08/22/2012 08:59 PM, Peter Constable wrote:

> But the bigger issue is that there's an important distinction between

> ReqFeatureIndex and mandatory r* features, as I've tried to point out already:

> ReqFeatureIndex is a property of a language system, whereas mandatory r*

> features are applicable to all language systems or, perhaps, even all scripts.



I responded to this with the following message:

OFF list: http://tech.groups.yahoo.com/group/mpeg-OTspec/message/837

OT list: http://www.indx.co.uk/biglistarchive/?mode=showpost&id=G7uvfDZuMaDe2oH2xjwk9H9tH



Could you please confirm you received that message (people have been reporting not receiving all messages in their Inboxes), and also give an update on whether you still think the "bigger issue" you describe is still an issue?



I won’t repeat my points from the message linked to above, but will say that



     (script, language, feature) -> lookups



is true of any registered feature as well as of the ReqFeatureIndex -- they all resolve to a bunch of lookups, given a script and language (or given the default language system for a script).



Thus, ReqFeatureIndex functionality can be completely replicated by a registered feature tag with the same name, so long as that feature tag is "required" to be applied.



Something like ‘ccmp’ functionality may have been a good candidate to put in ReqFeatureIndex – but we have ‘ccmp’, and so why put it in ReqFeatureIndex? In other words, the model of registered feature tags for “required” functionality seems to have superseded the ReqFeatureIndex facility.





All that said, I'm not sure I want to go ahead with the proposal to deprecate it, given that the questions (and some confusion) regarding its meaning and usage haven't been resolved by now, as far as I can see, even after several threads in the past couple of years on these lists.



Sairus

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